The present invention relates to a digital video encoder for use in a digital video apparatus and, particularly to a digital video encoder for converting a digital video signal into an analog video signal and outputting the analog video signal.
With digitization of video signals now proceeding, a digital video apparatus for displaying video on a DVD (Digital Versatile Disc), for example, includes a digital video encoder for converting a digital video signal into an analog video signal.
The analog video signal outputted from the digital video encoder comprises a horizontal synchronizing signal, a color burst, and a video signal. FIG. 5 is a diagram showing a waveform of an analog video signal outputted from a conventional digital video encoder. As shown in FIG. 5, the analog video signal comprises a horizontal synchronizing signal, a color burst, and a video signal with a pedestal level as a reference. Incidentally, a certain period from a start point of the horizontal synchronizing signal, which period is defined by analog video signal standards, is referred to as a horizontal blanking period.
The conventional digital video encoder determines the period from the start point of the horizontal synchronizing signal to a start point of the video signal by the following two methods. One method is to output the analog video signal while maintaining a relation between a horizontal synchronizing signal and a video signal of an input digital video signal as it is. The other method is to mask the video signal of the analog video signal during the horizontal blanking period.
However, with the method that maintains the relation between the horizontal synchronizing signal and the video signal of the input digital video signal as it is, when the horizontal synchronizing signal and the video signal of the input digital video signal overlap each other, the video signal is outputted in a state of overlapping both the horizontal synchronizing signal and the color burst of the analog video signal.
With the method of masking the video signal during the horizontal blanking period, in the case where to clamp the pedestal level of the analog video signal is time-consuming, the video signal of the analog video signal is outputted before the pedestal level is stabilized.
Thus, the conventional digital video encoder has a problem in that the video signal of the analog video signal may not be outputted stably.